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295 lines
8.5 KiB
295 lines
8.5 KiB
/* SPDX-License-Identifier: GPL-2.0-only */ |
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/* include/net/xdp.h |
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* |
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* Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc. |
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*/ |
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#ifndef __LINUX_NET_XDP_H__ |
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#define __LINUX_NET_XDP_H__ |
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#include <linux/skbuff.h> /* skb_shared_info */ |
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/** |
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* DOC: XDP RX-queue information |
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* |
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* The XDP RX-queue info (xdp_rxq_info) is associated with the driver |
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* level RX-ring queues. It is information that is specific to how |
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* the driver have configured a given RX-ring queue. |
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* |
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* Each xdp_buff frame received in the driver carry a (pointer) |
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* reference to this xdp_rxq_info structure. This provides the XDP |
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* data-path read-access to RX-info for both kernel and bpf-side |
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* (limited subset). |
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* |
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* For now, direct access is only safe while running in NAPI/softirq |
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* context. Contents is read-mostly and must not be updated during |
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* driver NAPI/softirq poll. |
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* |
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* The driver usage API is a register and unregister API. |
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* |
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* The struct is not directly tied to the XDP prog. A new XDP prog |
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* can be attached as long as it doesn't change the underlying |
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* RX-ring. If the RX-ring does change significantly, the NIC driver |
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* naturally need to stop the RX-ring before purging and reallocating |
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* memory. In that process the driver MUST call unregistor (which |
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* also apply for driver shutdown and unload). The register API is |
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* also mandatory during RX-ring setup. |
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*/ |
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enum xdp_mem_type { |
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MEM_TYPE_PAGE_SHARED = 0, /* Split-page refcnt based model */ |
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MEM_TYPE_PAGE_ORDER0, /* Orig XDP full page model */ |
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MEM_TYPE_PAGE_POOL, |
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MEM_TYPE_XSK_BUFF_POOL, |
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MEM_TYPE_MAX, |
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}; |
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/* XDP flags for ndo_xdp_xmit */ |
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#define XDP_XMIT_FLUSH (1U << 0) /* doorbell signal consumer */ |
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#define XDP_XMIT_FLAGS_MASK XDP_XMIT_FLUSH |
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struct xdp_mem_info { |
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u32 type; /* enum xdp_mem_type, but known size type */ |
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u32 id; |
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}; |
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struct page_pool; |
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struct xdp_rxq_info { |
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struct net_device *dev; |
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u32 queue_index; |
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u32 reg_state; |
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struct xdp_mem_info mem; |
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unsigned int napi_id; |
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} ____cacheline_aligned; /* perf critical, avoid false-sharing */ |
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struct xdp_txq_info { |
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struct net_device *dev; |
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}; |
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struct xdp_buff { |
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void *data; |
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void *data_end; |
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void *data_meta; |
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void *data_hard_start; |
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struct xdp_rxq_info *rxq; |
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struct xdp_txq_info *txq; |
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u32 frame_sz; /* frame size to deduce data_hard_end/reserved tailroom*/ |
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}; |
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static __always_inline void |
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xdp_init_buff(struct xdp_buff *xdp, u32 frame_sz, struct xdp_rxq_info *rxq) |
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{ |
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xdp->frame_sz = frame_sz; |
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xdp->rxq = rxq; |
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} |
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static __always_inline void |
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xdp_prepare_buff(struct xdp_buff *xdp, unsigned char *hard_start, |
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int headroom, int data_len, const bool meta_valid) |
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{ |
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unsigned char *data = hard_start + headroom; |
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xdp->data_hard_start = hard_start; |
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xdp->data = data; |
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xdp->data_end = data + data_len; |
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xdp->data_meta = meta_valid ? data : data + 1; |
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} |
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/* Reserve memory area at end-of data area. |
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* |
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* This macro reserves tailroom in the XDP buffer by limiting the |
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* XDP/BPF data access to data_hard_end. Notice same area (and size) |
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* is used for XDP_PASS, when constructing the SKB via build_skb(). |
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*/ |
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#define xdp_data_hard_end(xdp) \ |
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((xdp)->data_hard_start + (xdp)->frame_sz - \ |
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SKB_DATA_ALIGN(sizeof(struct skb_shared_info))) |
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static inline struct skb_shared_info * |
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xdp_get_shared_info_from_buff(struct xdp_buff *xdp) |
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{ |
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return (struct skb_shared_info *)xdp_data_hard_end(xdp); |
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} |
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struct xdp_frame { |
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void *data; |
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u16 len; |
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u16 headroom; |
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u32 metasize:8; |
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u32 frame_sz:24; |
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/* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time, |
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* while mem info is valid on remote CPU. |
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*/ |
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struct xdp_mem_info mem; |
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struct net_device *dev_rx; /* used by cpumap */ |
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}; |
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#define XDP_BULK_QUEUE_SIZE 16 |
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struct xdp_frame_bulk { |
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int count; |
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void *xa; |
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void *q[XDP_BULK_QUEUE_SIZE]; |
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}; |
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static __always_inline void xdp_frame_bulk_init(struct xdp_frame_bulk *bq) |
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{ |
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/* bq->count will be zero'ed when bq->xa gets updated */ |
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bq->xa = NULL; |
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} |
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static inline struct skb_shared_info * |
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xdp_get_shared_info_from_frame(struct xdp_frame *frame) |
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{ |
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void *data_hard_start = frame->data - frame->headroom - sizeof(*frame); |
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return (struct skb_shared_info *)(data_hard_start + frame->frame_sz - |
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SKB_DATA_ALIGN(sizeof(struct skb_shared_info))); |
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} |
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struct xdp_cpumap_stats { |
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unsigned int redirect; |
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unsigned int pass; |
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unsigned int drop; |
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}; |
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/* Clear kernel pointers in xdp_frame */ |
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static inline void xdp_scrub_frame(struct xdp_frame *frame) |
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{ |
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frame->data = NULL; |
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frame->dev_rx = NULL; |
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} |
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/* Avoids inlining WARN macro in fast-path */ |
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void xdp_warn(const char *msg, const char *func, const int line); |
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#define XDP_WARN(msg) xdp_warn(msg, __func__, __LINE__) |
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struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp); |
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struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf, |
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struct sk_buff *skb, |
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struct net_device *dev); |
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struct sk_buff *xdp_build_skb_from_frame(struct xdp_frame *xdpf, |
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struct net_device *dev); |
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int xdp_alloc_skb_bulk(void **skbs, int n_skb, gfp_t gfp); |
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struct xdp_frame *xdpf_clone(struct xdp_frame *xdpf); |
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static inline |
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void xdp_convert_frame_to_buff(struct xdp_frame *frame, struct xdp_buff *xdp) |
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{ |
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xdp->data_hard_start = frame->data - frame->headroom - sizeof(*frame); |
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xdp->data = frame->data; |
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xdp->data_end = frame->data + frame->len; |
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xdp->data_meta = frame->data - frame->metasize; |
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xdp->frame_sz = frame->frame_sz; |
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} |
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static inline |
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int xdp_update_frame_from_buff(struct xdp_buff *xdp, |
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struct xdp_frame *xdp_frame) |
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{ |
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int metasize, headroom; |
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/* Assure headroom is available for storing info */ |
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headroom = xdp->data - xdp->data_hard_start; |
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metasize = xdp->data - xdp->data_meta; |
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metasize = metasize > 0 ? metasize : 0; |
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if (unlikely((headroom - metasize) < sizeof(*xdp_frame))) |
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return -ENOSPC; |
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/* Catch if driver didn't reserve tailroom for skb_shared_info */ |
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if (unlikely(xdp->data_end > xdp_data_hard_end(xdp))) { |
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XDP_WARN("Driver BUG: missing reserved tailroom"); |
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return -ENOSPC; |
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} |
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xdp_frame->data = xdp->data; |
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xdp_frame->len = xdp->data_end - xdp->data; |
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xdp_frame->headroom = headroom - sizeof(*xdp_frame); |
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xdp_frame->metasize = metasize; |
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xdp_frame->frame_sz = xdp->frame_sz; |
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return 0; |
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} |
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/* Convert xdp_buff to xdp_frame */ |
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static inline |
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struct xdp_frame *xdp_convert_buff_to_frame(struct xdp_buff *xdp) |
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{ |
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struct xdp_frame *xdp_frame; |
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if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL) |
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return xdp_convert_zc_to_xdp_frame(xdp); |
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/* Store info in top of packet */ |
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xdp_frame = xdp->data_hard_start; |
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if (unlikely(xdp_update_frame_from_buff(xdp, xdp_frame) < 0)) |
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return NULL; |
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/* rxq only valid until napi_schedule ends, convert to xdp_mem_info */ |
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xdp_frame->mem = xdp->rxq->mem; |
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return xdp_frame; |
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} |
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void xdp_return_frame(struct xdp_frame *xdpf); |
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void xdp_return_frame_rx_napi(struct xdp_frame *xdpf); |
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void xdp_return_buff(struct xdp_buff *xdp); |
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void xdp_flush_frame_bulk(struct xdp_frame_bulk *bq); |
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void xdp_return_frame_bulk(struct xdp_frame *xdpf, |
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struct xdp_frame_bulk *bq); |
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/* When sending xdp_frame into the network stack, then there is no |
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* return point callback, which is needed to release e.g. DMA-mapping |
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* resources with page_pool. Thus, have explicit function to release |
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* frame resources. |
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*/ |
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void __xdp_release_frame(void *data, struct xdp_mem_info *mem); |
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static inline void xdp_release_frame(struct xdp_frame *xdpf) |
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{ |
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struct xdp_mem_info *mem = &xdpf->mem; |
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/* Curr only page_pool needs this */ |
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if (mem->type == MEM_TYPE_PAGE_POOL) |
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__xdp_release_frame(xdpf->data, mem); |
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} |
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int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq, |
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struct net_device *dev, u32 queue_index, unsigned int napi_id); |
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void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq); |
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void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq); |
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bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq); |
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int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq, |
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enum xdp_mem_type type, void *allocator); |
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void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq); |
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/* Drivers not supporting XDP metadata can use this helper, which |
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* rejects any room expansion for metadata as a result. |
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*/ |
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static __always_inline void |
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xdp_set_data_meta_invalid(struct xdp_buff *xdp) |
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{ |
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xdp->data_meta = xdp->data + 1; |
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} |
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static __always_inline bool |
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xdp_data_meta_unsupported(const struct xdp_buff *xdp) |
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{ |
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return unlikely(xdp->data_meta > xdp->data); |
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} |
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static inline bool xdp_metalen_invalid(unsigned long metalen) |
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{ |
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return (metalen & (sizeof(__u32) - 1)) || (metalen > 32); |
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} |
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struct xdp_attachment_info { |
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struct bpf_prog *prog; |
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u32 flags; |
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}; |
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struct netdev_bpf; |
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void xdp_attachment_setup(struct xdp_attachment_info *info, |
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struct netdev_bpf *bpf); |
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#define DEV_MAP_BULK_SIZE XDP_BULK_QUEUE_SIZE |
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#endif /* __LINUX_NET_XDP_H__ */
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